Apparatus and method for holding a piece in a bore

ABSTRACT

An assembly includes a piece to be held in a bore and a device in which the piece is inserted for holding the piece in the bore. The device comprises a cylindrical sleeve having a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface. The fins are skewed in a same circumferential direction relative to radial planes of the sleeve. The sleeve and the fins are integrally formed of resilient flexible plastic. The flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece. The device can be used as part of a combination that includes a body having a bore therein, and can be used in a method of holding a piece in a bore of a body.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of provisional application No. 60/415,145 filed Oct. 2, 2002; 60/415,240 filed Oct. 2, 2002, and 60/415,203 filed Oct. 2, 2002, all incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] This invention relates to an apparatus and method for holding a piece in a bore, The invention will be described in its application to the use of a fastener retainer for holding a fastener, such as a bolt, in a bore of a body, such as a panel, for example, but it will become apparent that the invention has broader utility.

[0003] The use of fastener retainers to pre-attach bolts, studs, or other fasteners to a workpiece, such as a panel, in preparation for a subsequent assembly operation is well known. Such pre-attachment improves production efficiency by eliminating the need for manual placement of the fasteners as parts of the assembly operation. In a typical application, a bolt (or other fastener) is inserted into a plastic annular retainer which is designed to retain the bolt within a smooth-walled bore of a workpiece. The retainer, which has an outer diameter slightly larger than that of the bore, is pressed into the bore, where it is held by resilient frictional engagement with the bore wall, thus pre-attaching the bolt to the workpiece. The workpiece may subsequently be associated with a second workpiece having a threaded bore which is axially aligned with the bore of the first workpiece, and the two workpieces may then be securely assembled to each other by engaging the bolt with the threaded bore of the second workpiece. See, for example, U.S. Pat. Nos. RE 36,164 and 6,039,525.

[0004] In practical use of such retainers, it is often important that the holding power of the retainer to the fastener and the holding power of the retainer to the workpiece bore be such that the retained fastener may, if inadvertently bumped, slide axially of the retainer without the retainer slipping out of the workpiece bore. It is also desirable to provide a retainer that accommodates misalignment of the bores and that permits the fastener to be tilted relative to the axis of the retainer. Furthermore, it is desirable that the design of the retainer readily accommodate varying requirements for retainer holding power and varying fastener and bore diameters, and that the retainer be capable of being manufactured simply and economically.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide an improved apparatus and an improved method for holding a piece in a bore.

[0006] It is another object of the invention to provide an improved assembly of a piece to be held in a bore and a piece-holding device, and more particularly, an improved assembly of a fastener retainer and a fastener.

[0007] It is a further object of the invention to provide an improved combination of a body having a bore therein, a piece-holding device inserted in the bore, and a piece inserted in and held by the piece-holding device, and more particularly, to an improved combination of a body having a bore therein, a fastener retainer, and a fastener.

[0008] It is another object of the invention to provide an improved assembly of the foregoing type, an improved combination of the foregoing type, and an improved method for holding a piece in a bore in which the piece-holding device is readily adaptable to varying requirements for holding power and is capable of being manufactured simply and economically.

[0009] The foregoing objects, as well as other aspects, features and advantages of the invention, will be more fully appreciated from the following description of preferred embodiments taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010]FIG. 1 is a perspective view of a piece-holding device useful in the invention;

[0011]FIG. 2 is a side elevation view of the piece-holding device of the first embodiment;

[0012]FIG. 3 is an end view of the piece-holding device of the first embodiment;

[0013]FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

[0014]FIG. 5 is an end view of a second embodiment of a piece-holding device useful in the invention;

[0015]FIG. 6 is a sectional view taken along line 6-6 in FIG. 5;

[0016]FIG. 7 is an end view of a third embodiment of a piece-holding device useful in the invention;

[0017]FIG. 8 is sectional view taken along line 8-8 in FIG. 7;

[0018]FIG. 9 is an end view of a fourth embodiment of a piece-holding device useful in the invention;

[0019]FIG. 10 is a plan view of the piece-holding device of the fourth embodiment;

[0020]FIG. 11 is a sectional view taken along line 11-11 in FIG. 9; and

[0021]FIG. 12 is an exploded perspective view showing the use of the invention with a retainer of the fourth embodiment and a bolt.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] As shown in FIGS. 1-4, a first embodiment of a device 10 useful in an assembly, combination, and method according to the invention comprises a cylindrical sleeve 12 having a series of fins 14 extending longitudinally of an inner surface 16 of the sleeve and projecting inwardly from the inner surface. The fins are spaced from each other circumferentially of the sleeve with tips 18 extending along the length of the sleeve and disposed to engage an outer surface of a piece inserted into the sleeve, as later described. In the embodiment there are nine fins, but the number of fins can be varied to meet the need of particular applications of the invention.

[0023] The sleeve and the fins are integrally formed of a resilient flexible plastic, e.g., a polyester elastomer, and are preferably skewed in a same circumferential direction relative to radial planes of the sleeve. The inclination angles of the fins are preferably uniform. The flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece. For this purpose, the dimension of each fin along the direction of its inward projection is preferably substantially greater than the thickness of the fin.

[0024] In order to facilitate insertion of the retainer into a bore, either or both of end portions 20 of the sleeve are chamfered. Accordingly, the end portions of the sleeve have an outer diameter that increases away from the respective longitudinal ends of the sleeve.

[0025] In the first embodiment, the longitudinal ends 22 of the fins are spaced from the longitudinal ends, respectively, of the sleeve. The end portions 20 of the sleeve have an inner diameter that slightly increases between the respective longitudinal ends of the sleeve and the fins.

[0026] To facilitate the insertion of a bolt or other fastener (e.g., a pin or stud) into the retainer, the fins are preferably tapered. To provide the desired taper of the fins, the longitudinal ends 22 of the fins extend away from the respective longitudinal ends 24 of the sleeve and away from the inner surface 16 of the sleeve. The longitudinal side surfaces 26 of the fins are preferably trapezoidal. The longitudinal ends of the sleeve are preferably flat. If the bolt or other fastener is sufficiently tapered at its leading end, the fins need not be tapered, i.e., the longitudinal side surfaces 26 of the fins may be rectangular.

[0027]FIGS. 5 and 6 illustrate a second embodiment of a piece-holding device useful in the invention, which is similar to the first embodiment except that the inner diameter of the end portions of the sleeve is uniform between the longitudinal ends of the sleeve and the ends of the fins.

[0028]FIGS. 7 and 8 illustrate a third embodiment of a piece-holding device useful in the invention, in which the fins extend all the way to the longitudinal ends of the sleeve.

[0029]FIGS. 9-11 illustrate a fourth embodiment of a piece-holding device useful in the invention. In this embodiment, the fins are similar to the fins of the third embodiment, but at three locations spaced 120° apart abutments 28 are provided, the ends of which are spaced from the respective longitudinal ends of the sleeve.

[0030] In all of the embodiments described, the piece-holding devices used in the assemblies, combinations, and methods of the invention can be manufactured by injection molding of a plastic such as high-density polyethylene. In the embodiment of FIGS. 9-11, the longitudinal ends of the abutments 28 may engage ejector pins of molding apparatus to eject the molded retainer from a mold. In the form shown, slots 30 are provided in the sleeve for insertion of the ejector pins. The slots may be eliminated if the inward projection of the abutments 28 is sufficient to permit the ejector pins to engage substantially flat surfaces of the abutments internally of the sleeve 12. Th inward projection of the abutments (toward the axis of the sleeve) is less than the inward projection of the fins by an amount that is sufficient to ensure that the abutments do not engage a bolt or other fastener inserted axially into the sleeve 12. Opposite longitudinal ends of the abutments may be chamfered or tapered to minimize obstruction to insertion of a fastener in the event of axial misalignment of the fastener with the retainer during insertion.

[0031]FIG. 12 illustrates an assembly, combination, and method of the invention using a retainer 10 of the fourth embodiment (representative of the use of all embodiments) for holding a bolt 32 in a bore 34 of a body 36. Typically, the retainer will be pre-assembled with the bolt, and the resulting pre-assembly then inserted into and frictionally engaged with the bore of the body, thus pre-attaching the bolt to the body. However, the retainer may first be pressed into the bore and then the bolt inserted into the retainer.

[0032] The outer diameter of the sleeve 12 is slightly greater than the inner diameter of the bore 34 to allow for resilient frictional engagement of the sleeve with the wall of the bore. The diameters of the outer surface of the sleeve and the bore wall are preferably sufficiently close to one another to avoid buckling of the sleeve within the bore, whereby essentially the entirety of the cylindrical outer surface of the sleeve between the chamfered ends will be in engagement with the complementary cylindrical inner surface of the bore.

[0033] When the shank 38 of the bolt is pressed into the retainer, the outer surface of the shank (typically the crests of the threads in the case of a bolt) engages the tips of the fins 14 and thereby deflects the fins circumferentially and slightly outwardly. As a result, the fins center the bolt within the sleeve of the retainer and hold the bolt within the retainer. As is apparent in FIG. 12, the bolt may project from the bore 34 of the body 36 for engagement with a threaded bore 40 of a second body 42, thereby to join the second body to the first body. The bodies may be panels to be joined, for example. The construction of the invention accommodates misalignment of the bolt and the retainer as well as misalignment of the bodies to be joined. It is preferred that the frictional force between the outer surface of the sleeve of the retainer and the inner surface of the bore be greater than the frictional force between the bolt and the retainer, so that adjustment of the bolt relative to the retainer does not shift the retainer relative to the bore.

[0034] As a non-limiting example of dimensions of a piece-holding device useful in an assembly of the invention with an M6 bolt, the axial length of the sleeve may be about 5.0 mm., and the outer diameter of the sleeve may be about 8.75 mm with a sleeve wall thickness of about 0.625 mm. The fin thickness may be about 0.46 mm. The inward extension of each fin along one trapezoidal side may be about 1.559 mm and along the opposite trapezoidal side may be about 1.270 mm. Thus, the inward extension of each fin is substantially greater than the thickness of the fin (about three times as great in the embodiment). Also, in the embodiment the fin thickness is substantially uniform, except at the pointed tip. An angle between a radius and the shorter trapezoidal side of a fin may be about 31° 24′ 15″. An angle defined between radii extending through the intersections of the shorter trapezoidal sides of adjacent fins with the inner surface of the sleeve may be about 40°. The axial length of each fin at its tip may be about 2.9 mm. In their relaxed state, the tips of the fins may lie tangentially on a circle with a diameter of about 5.494 mm. In the fourth embodiment, the axial length of each abutment 28 may be about 2.99 mm.

[0035] While preferred embodiments of the invention have been shown and described, those skilled in the art will recognize that various changes can be made without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims. For example, an assembly or combination of the invention may comprise a group of piece-holding devices and a pin or stud held by such devices in a long bore. As a further example, a device used in a method of the invention may be used as a spacer or a washer and may be used in multiples to provide a group of such devices spaced apart, e.g., for holding a pin or stud in a long bore. 

1. An assembly comprising a piece to be held in a bore and a device in which the piece is inserted for holding the piece in the bore, wherein the device comprises: a cylindrical sleeve constructed to be inserted into the bore and held therein by engagement of its outer surface with an inner surface of the bore; and a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips disposed to engage an outer surface of a piece inserted into the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed in a same circumferential direction relative to radial planes of the sleeve, the dimension of each fin along the direction of its inward projection is substantially greater than the thickness of the fin, and the flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece.
 2. An assembly according to claim 1, wherein the fins have longitudinal ends that face longitudinal ends of the sleeve, respectively, and wherein at least one of the longitudinal ends of the fins extends away from the respective longitudinal end of the sleeve and away from the inner surface of the sleeve.
 3. An assembly according to claim 2, wherein each fin has trapezoidal longitudinal side surfaces.
 4. An assembly according to claim 1, wherein the device is formed of molded plastic and further comprises a plurality of abutments projecting inwardly from the inner surface of the sleeve for engagement with ejector pins of molding apparatus.
 5. An assembly according to claim 4, wherein the abutments are spaced inwardly from the longitudinal ends of the sleeve, and the sleeve has slots aligned with the abutments to permit engagement of the ejector pins with the abutments.
 6. An assembly according to claim 1, wherein the piece is inserted in the device and has a shank that engages tips of the fins and deflects the fins.
 7. An assembly according to claim 6, wherein the piece is a bolt.
 8. An assembly according to claim 1, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve.
 9. An assembly according to claim 1, wherein the fins extend to the longitudinal ends of the sleeve.
 10. An assembly according to claim 1, wherein end portions of the sleeve adjacent to the longitudinal ends of the sleeve, respectively, have an outer diameter that increases away from the respective longitudinal ends of the sleeve.
 11. An assembly according to claim 10, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have a substantially uniform inner diameter between the respective longitudinal ends of the sleeve and the fins.
 12. An assembly according to claim 10, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have an inner diameter that increases between the respective longitudinal ends of the sleeve and the fins.
 13. An assembly according to claim 1, wherein the longitudinal ends of the sleeve are flat.
 14. An assembly comprising a piece to be held in a bore and a device in which the piece is inserted for holding the piece in the bore, wherein the device comprises: a cylindrical sleeve; and a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips disposed to engage an outer surface of a piece inserted into the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed relative to radial planes of the sleeve, the flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece, and each fin is tapered by having at least one longitudinal end that extends away from a corresponding longitudinal end of the sleeve and away from the inner surface of the sleeve.
 15. An assembly according to claim 14, wherein each fin has trapezoidal longitudinal side surfaces.
 16. An assembly according to claim 14, wherein the fins are skewed in a same circumferential direction relative to radial planes of the sleeve and the dimension of each fin along the direction of its inward projection is substantially greater than the thickness of the fin.
 17. An assembly according to claim 14, wherein the device is formed of molded plastic and further comprises a plurality of abutments projecting inwardly from the inner surface of the sleeve for engagement with ejector pins of molding apparatus.
 18. An assembly according to claim 17, wherein the abutments are spaced inwardly from the longitudinal ends of the sleeve, and the sleeve has slots aligned with the abutments to permit engagement of the ejector pins with the abutments.
 19. An assembly according to claim 14, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve.
 20. An assembly according to claim 14, wherein the fins extend to the longitudinal ends of the sleeve.
 21. An assembly according to claim 14, wherein end portions of the sleeve adjacent to the longitudinal ends of the sleeve, respectively, have an outer diameter that increases away from the respective longitudinal ends.
 22. An assembly according to claim 21, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have a substantially uniform inner diameter between the respective longitudinal ends of the sleeve and the fins.
 23. An assembly according to claim 21, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have an inner diameter that increases between the respective longitudinal ends of the sleeve and the fins.
 24. An assembly according to claim 14, wherein the longitudinal ends of the sleeve are flat.
 25. An assembly according to claim 14, wherein the piece is inserted in the device and has a shank that engages tips of the fins and deflects the fins.
 26. An assembly according to claim 25, wherein the piece is a bolt.
 27. A combination comprising a body having a bore therein, a piece-holding device inserted in the bore, and a piece inserted in and held by the piece-holding device, wherein the piece-holding device comprises: a cylindrical sleeve held in the bore by engagement of its outer surface with an inner surface of the bore; and a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips that engage an outer surface of the piece inserted in the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed in a same circumferential direction relative to radial planes of the sleeve, the dimension of each fin along the direction of its inward projection is substantially greater than the thickness of the fin, and the fins are deflected by engagement with the inserted piece.
 28. A combination according to claim 27, wherein the fins have longitudinal ends that face longitudinal ends of the sleeve, respectively, and wherein at least one of the longitudinal ends of the fins extends away from the respective longitudinal end of the sleeve and away from the inner surface of the sleeve.
 29. A combination according to claim 28, wherein each fin has trapezoidal longitudinal side surfaces.
 30. A combination according to claim 27, wherein the device is formed of molded plastic and further comprises a plurality of abutments projecting inwardly from the inner surface of the sleeve for engagement with ejector pins of molding apparatus.
 31. A combination according to claim 30, wherein the abutments are spaced inwardly from the longitudinal ends of the sleeve, and the sleeve has slots aligned with the abutments to permit engagement of the ejector pins with the abutments.
 32. A combination according to claim 27, wherein the piece has a shank that engages tips of the fins and deflects the fins.
 33. A combination according to claim 32, wherein the piece is a bolt.
 34. A combination according to claim 27, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve.
 35. A combination according to claim 27, wherein the fins extend to the longitudinal ends of the sleeve.
 36. A combination according to claim 27, wherein end portions of the sleeve adjacent to the longitudinal ends of the sleeve, respectively, have an outer diameter that increases away from the respective longitudinal ends of the sleeve.
 37. A combination according to claim 36, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have a substantially uniform inner diameter between the respective longitudinal ends of the sleeve and the fins.
 38. A combination according to claim 36, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have an inner diameter that increases between the respective longitudinal ends of the sleeve and the fins.
 39. A combination according to claim 27, wherein the longitudinal ends of the sleeve are flat.
 40. A combination comprising a body having a bore therein, a piece-holding device inserted in the bore, and a piece inserted in and held by the piece-holding device, wherein the piece-holding device comprises: a cylindrical sleeve; and a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips disposed to engage an outer surface of a piece inserted into the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed relative to radial planes of the sleeve, the flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece, and each fin is tapered by having at least one longitudinal end that extends away from a corresponding longitudinal end of the sleeve and away from the inner surface of the sleeve.
 41. A combination according to claim 40, wherein each fin has trapezoidal longitudinal side surfaces.
 42. A combination according to claim 40, wherein the fins are skewed in a same circumferential direction relative to radial planes of the sleeve and the dimension of each fin along the direction of its inward projection is substantially greater than the thickness of the fin.
 43. A combination according to claim 40, wherein the device is formed of molded plastic and further comprises a plurality of abutments projecting inwardly from the inner surface of the sleeve for engagement with ejector pins of molding apparatus.
 44. A combination according to claim 43, wherein the abutments are spaced inwardly from the longitudinal ends of the sleeve, and the sleeve has slots aligned with the abutments to permit engagement of the ejector pins with the abutments.
 45. A combination according to claim 40, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve.
 46. A combination according to claim 40, wherein the fins extend to the longitudinal ends of the sleeve.
 47. A combination according to claim 40, wherein end portions of the sleeve adjacent to the longitudinal ends of the sleeve, respectively, have an outer diameter that increases away from the respective longitudinal ends.
 48. A combination according to claim 47, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have a substantially uniform inner diameter between the respective longitudinal ends of the sleeve and the fins.
 49. A combination according to claim 47, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have an inner diameter that increases between the respective longitudinal ends of the sleeve and the fins.
 50. A combination according to claim 40, wherein the longitudinal ends of the sleeve are flat.
 51. A combination according to claim 40, wherein the piece is a bolt.
 52. A method of holding a piece in a bore of a body, comprising: providing a piece-holding device having a cylindrical sleeve constructed to be inserted into the bore and held therein by engagement of its outer surface with an inner surface of the bore and having a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips disposed to engage an outer surface of a piece inserted into the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed in a same circumferential direction relative to radial planes of the sleeve, the dimension of each fin along the direction of its inward projection is substantially greater than the thickness of the fin, and the flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece; inserting the piece-holding device in the bore with its outer surface pressed into engagement with an inner surface of the bore; and inserting the piece in the sleeve of the piece-holding device with the outer surface of the piece engaging tips of the fins and deflecting the fins.
 53. A method according to claim 52, wherein the piece holding device is inserted in the bore and then the piece is inserted in the device.
 54. A method according to claim 52, wherein the piece is inserted in the piece-holding device and then the device and the piece are inserted in the bore.
 55. A method according to claim 52, wherein the fins have longitudinal ends that face longitudinal ends of the sleeve, respectively, and wherein at least one of the longitudinal ends of the fins extends away from the respective longitudinal end of the sleeve and away from the inner surface of the sleeve.
 56. A method according to claim 55, wherein each fin has trapezoidal longitudinal side surfaces.
 57. A method according to claim 52, wherein the device is formed of molded plastic and further comprises a plurality of abutments projecting inwardly from the inner surface of the sleeve for engagement with ejector pins of molding apparatus.
 58. A method according to claim 57, wherein the abutments are spaced inwardly from the longitudinal ends of the sleeve, and the sleeve has slots aligned with the abutments to permit engagement of the ejector pins with the abutments.
 59. A method according to claim 52, wherein the piece is a bolt.
 60. A method according to claim 52, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve.
 61. A method according to claim 52, wherein the fins extend to the longitudinal ends of the sleeve.
 62. A method according to claim 52, wherein end portions of the sleeve adjacent to the longitudinal ends of the sleeve, respectively, have an outer diameter that increases away from the respective longitudinal ends of the sleeve.
 63. A method according to claim 62, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have a substantially uniform inner diameter between the respective longitudinal ends of the sleeve and the fins.
 64. A method according to claim 62, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have an inner diameter that increases between the respective longitudinal ends of the sleeve and the fins.
 65. A method according to claim 1, wherein the longitudinal ends of the sleeve are flat.
 66. A method of holding a piece in a bore of a body, comprising: providing a piece-holding device having a cylindrical sleeve constructed to be inserted into the bore and held therein by engagement of its outer surface with an inner surface of the bore and having a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips disposed to engage an outer surface of a piece inserted into the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed relative to radial planes of the sleeve, the flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece, and each fin is tapered by having at least one longitudinal end that extends away from a corresponding longitudinal end of the sleeve and away from the inner surface of the sleeve; inserting the piece-holding device in the bore with its outer surface pressed into engagement with an inner surface of the bore; and inserting the piece in the sleeve of the piece-holding device with the outer surface of the piece engaging tips of the fins and deflecting the fins.
 67. A method according to claim 66, wherein each fin has trapezoidal longitudinal side surfaces.
 68. A method according to claim 66, wherein the fins are skewed in a same circumferential direction relative to radial planes of the sleeve and the dimension of each fin along the direction of its inward projection is substantially greater than the thickness of the fin.
 69. A method according to claim 66, wherein the device is formed of molded plastic and further comprises a plurality of abutments projecting inwardly from the inner surface of the sleeve for engagement with ejector pins of molding apparatus.
 70. A method according to claim 69, wherein the abutments are spaced inwardly from the longitudinal ends of the sleeve, and the sleeve has slots aligned with the abutments to permit engagement of the ejector pins with the abutments.
 71. A method according to claim 66, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve.
 72. A method according to claim 66, wherein the fins extend to the longitudinal ends of the sleeve.
 73. A method according to claim 66, wherein end portions of the sleeve adjacent to the longitudinal ends of the sleeve, respectively, have an outer diameter that increases away from the respective longitudinal ends.
 74. A method according to claim 73, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have a substantially uniform inner diameter between the respective longitudinal ends of the sleeve and the fins.
 75. A method according to claim 73, wherein the longitudinal ends of the fins are spaced from the respective longitudinal ends of the sleeve and said end portions have an inner diameter that increases between the respective longitudinal ends of the sleeve and the fins.
 76. A method according to claim 66, wherein the longitudinal ends of the sleeve are flat.
 77. A method according to claim 66, wherein the piece is a bolt.
 78. A method according to claim 66, wherein the piece holding device is inserted in the bore and then the piece is inserted in the device.
 79. A method according to claim 66, wherein the piece is inserted in the piece-holding device and then the device and the piece are inserted in'the bore.
 80. A method of joining a first workpiece having a bore therethrough to a second workpiece having a bore, comprising: providing a piece-holding device having a cylindrical sleeve constructed to be inserted into the bore of the first workpiece and held therein by engagement of its outer surface with an inner surface of the bore of the first workpiece and having a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips disposed to engage an outer surface of a piece inserted into the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed in a same circumferential direction relative to radial planes of the sleeve, the dimension of each fin along the direction of its inward projection is substantially greater than the thickness of the fin, and the flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece; inserting the piece-holding device in the bore of the first workpiece with its outer surface pressed into engagement with an inner surface of the bore of the first workpiece; inserting the piece in the sleeve of the piece-holding device and through the bore of the first workpiece, with the outer surface of the piece engaging tips of the fins and deflecting the fins; aligning the bore of the second workpiece with an end of the piece beyond the bore of the first workpiece; and fixing the end of the piece in the bore of the second workpiece.
 81. A method according to claim 80, wherein the piece holding device is inserted in the bore in the first workpiece and then the piece is inserted in the device.
 82. A method according to claim 80, wherein the piece is inserted in the piece-holding device and then the device and the piece are inserted in the bore of the first workpiece.
 83. A method according to claim 80, wherein the piece is a bolt, and the bolt and the bore in the second workpiece have complementary threads by which the bolt is fixed in the bore of the second workpiece.
 84. A method of joining a first workpiece having a bore therethrough to a second workpiece having a bore, comprising: providing a piece-holding device having a cylindrical sleeve constructed to be inserted into the bore in the first workpiece and held therein by engagement of its outer surface with an inner surface of the bore in the first workpiece and having a series of fins extending longitudinally of an inner surface of the sleeve and projecting inwardly from the inner surface of the sleeve, the fins being spaced from each other circumferentially of the sleeve with tips disposed to engage an outer surface of a piece inserted into the sleeve, wherein the sleeve and the fins are integrally formed of resilient flexible plastic, the fins are skewed relative to radial planes of the sleeve, the flexibility of the fins is such that the fins can be readily deflected when engaged by an inserted piece, and each fin is tapered by having at least one longitudinal end that extends away from a corresponding longitudinal end of the sleeve and away from the inner surface of the sleeve; inserting the piece-holding device in the bore of the first workpiece with its outer surface pressed into engagement with an inner surface of the bore of the first workpiece; inserting the piece in the sleeve of the piece-holding device and through the bore of the first workpiece, with the outer surface of the piece engaging tips of the fins and deflecting the fins; aligning the bore of the second workpiece with an end of the piece beyond the bore of the first workpiece; and fixing the end of the piece in the bore of the second workpiece.
 85. A method according to claim 84, wherein the piece holding device is inserted in the bore in the first workpiece and then the piece is inserted in the device.
 86. A method according to claim 84, wherein the piece is inserted in the piece-holding device and then the device and the piece are inserted in the bore of the first workpiece.
 87. A method according to claim 84, wherein the piece is a bolt, and the bolt and the bore in the second workpiece have complementary threads by which the bolt is fixed in the bore of the second workpiece. 